Abstract
In the frog taste disc, wing cells, but not rod cells display inward currents in response to external arachidonic acid (AA). In the present study, we investigated the biophysical properties of lipid mediator-induced currents while recording the whole cell currents of isolated rod and wing cells in frog taste discs. When AA (50 μM) was applied extracellularly, the wing cells displayed parabolic inward currents. The current conducted poorly at the membrane potential of -80 mV despite the presence of AA, but their conductance increased at a resting potential of -50 mV. AA (50 μM) elicited inward currents of -40 ± 9 pA (N=10) in the wing cells. Linoleic, linolenic and docosahexaenoic acids induced similar currents in the wing cells. Although the rod cells display only enhancement of the outward currents in response to external AA, intracellular dialysis with 50 μM 1-oleoyl-2-acetyl-sn-glycerol (OAG), a synthetic analog of diacylglycerol (DAG), induced inward currents of -155 ± 36 pA (N=4) at -50 mV in 4 of 6 rod cells. I-V relationships of OAG-induced currents were almost linear. The wing cells did not respond to internal OAG. The results suggest that frog rod and wing cells may have different roles in taste transduction. [J Physiol Sci. 2007;57 Suppl:S108]
